CANNES, France--The so-far disappointing 2003 Cannes Film Festival stirred from its torpor over the weekend with sex, violence and dogma. This being Cannes, dogma got the most attention, as Lars Von Trier, a founder of the minimalist Dogma movement, unveiled his three-hour "Dogville." This is one of the most confounding and exasperating films of the festival, and maybe it is brilliant, but I will not be able to determine that until I have recovered from the ordeal of sitting through it.